Skimmer Types

[Hotpuppy]

Is anyone using a counter-current airstone driven skimmer? If so, what are the drawbacks?

I'm contemplating making one based on PR Escobal's book Aquatic Systems Engineering. The chief advantage to it is that is seems like an air pump and a low-flow pump would be substantially less expensive to operate then a venturi skimmer.

I've heard that they require more maintenance... but changing an air stone isn't that big of a deal. I've seen evidence that the pond folks are using them.

I have a adequate venturi driven skimmer that was given to me. I made some field expedient repairs to it, and it's a nice unit. I'm not going to name the brand because they are nice folks and it's an expensive unit. However, they are suggesting running with something like an Iwaki 55, which is a 200 watt draw. The Venturi presents about 20 feet of head to the pump which will reduce flow to 500 gph on this pump. It seems to me that this is a good backup, but a expensive way to generate air bubbles.

I can get Limewood (aka Basswood) for next to nothing and make my own airstones.... or simply purchase them.

Running the Iwaki is $17.28/mo at 12c/kwh, assuming a 200 watt draw (it's technically 192 watts, so I rounded up a bit).

A slow counter-current could be driven by a submerisble eheim pump for around 20 watts or less. Very likely a 10 watt model would deliver the 100 gph or so that is needed. An air pump can't be that expensive to run, maybe 10 watts?

Any thoughts? I realize I'm being a cheapo here, but I want a solid system that doesn't require a zoo's power budget.

 

[CaptiveReef]

Using Counter Current Venturi skimmer.

Using Counter Current Venturi skimmer.

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Here is the skimmer I use.

CaptiveReef

 

[Mike31154]

Apologies for sticking my beak into the large tank forum, I don't have a large tank. But I do use a wooden air diffuser, counter current skimmer and am very pleased with the performance. Low power requirements as you mentioned, with small powerhead & air pump. I think my set up uses less than 20 watts and is dead silent. I build my own wooden air diffusers out of a basswood plank. They last for months, seem to get better with age/after a break in period. From what I've seen, read, imbibed & other wise collected, the two major factors in skimmer performance are contact time between air bubble/water and air bubble size (smaller is better). I have yet to see any of the newer tech skimmers significantly improve on the wooden air diffuser bubble production. Mr Escobal's writings & research are one of the reasons I'm reluctant to change my old school skimmer ways. If you've got room for a 6 or 8 foot skimmer tube & an air pump to produce bubbles at that head pressure, I'd say wood/counter current is the way to go.

 

[CaptiveReef]

Mike31154 check out post above yours.

Mike31154 check out post above yours.

Mike and Hotpuppy, I have designed a lot of skimmers over the years, the taller the skimmer the more air pressure you have to use to get the lime wood air diffuser to work properly. Daniel Knop sells a line of skimmers that use multiple 4-6 inch lime wood air diffusers that are on a circular air manifold.
The only fall back with using lime wood air diffusers is that they break down quickly and get clogged up reducing the efficiency and performance of the skimmer.
If you check out my post above yours, you will see my skimmer design, it is a self leveling counter current skimmer that uses a venturi to produce bubbles and has an additional powerhead for added flow through skimmer. It is easy to build and works incredible! There is no tinkering, except cleaning the skimmate at the top.

CaptiveReef :thumbsup: